Vibration generating apparatus



May 18, 1937. E. H. LUDEMAN. JR 2,080,727

VIBRATION GENERATING AY PARATUS Filed Sept. 15, 1934 Patented May 18, 1937 Edwin H. Ludeman, Jr., Brooklyn, N. Y. \Application September 15, 1934, Serial No. 744,255 I 14 Claims.

This invention relates to apparatus for inter-' nally vibrating plastic orgranular materials, for example, concrete.

The primary object of the invention is the provision of a device which may be wholly or partially submerged in the material to be vibrat ed and which will set up vibrations in the material, by reason of high-frequency volumetric changes.

A furtherobject is the provision of such a device which, while undergoing volumetric changes for the purpose of vibrating a mass in which it is submerged, will also be mechanically vibrated by the impact of its internal moving parts, which vibrations will also be communicated to the mass.

A still further object is the provision of a vibrator which may be operated by fluid pressure, such as compressed air, readily obtainable in conjunction with construction work, which will be economical to operate, inexpensive to manufacture, and easily kept in working order at minimum expense.

Other objects and advantages of the invention will be apparent @ring the course of the following description of the present preferred embodiment of the invention.

The invention is especially adapted for use with l nated, resulting in the thorough compaction of the mass, the complete filling of the form, and thorough bonding with the reenforcement.

In, the drawing: Fig. l is a longitudinal section of the vibrator taken on line ll of Figs. 2, 3, 4, and 5. Figs. 2, 3, 4, and 5 are cross-sectional views on lines 2-2, 3-3, 44 and 5--5 respectively of Fig. 1. Fig. 6 is a vertical section through a mass of plastic concrete contained in a wooden form showing the vibrator in a work-' ing position.

Similar numerals refer to similar parts throughout the several views.

Referring to the drawing, .the. embodiment shown, which is designed to be operated by compressed air, is constructed generally as follows: a body comprising a metal cylin'der' Ill with an extension piece H, and other associated parts forms the framework of the device. On the outside of the cylinder and extension piece a heavy cylindrical elastic casing I2 of rubber or other suitable material is secured, its ends bound airtight. Ports in the wall of the cylinder l0 and the extension piece Il communicate with the interior of the elastic casing l2 to permit the entrance to and exhaust ironithe casing of the compressed air or other fluid. In'side the metal cylinder I0 is high speed automatic valve mechanism which controls the fluid, alternateljpppening and closing the inlet and exhaust ports? ?'The resulting alternate admission and exhaustion compressed air to and from the inside of the elastic casing l2 causes it alternately to expand and to contract, which action, being at high frequency, sets up vibrations in the material surrounding the casing. Moreover, the moving part of the valve mechanism alternately strikes opposite ends of the passage in which it moves, its impacts setting up other vibrations in the device which'a're communicated to the surrounding material,

The compressed air is supplied to the vibrator from a suitable source through the inner flexible hose l6, equipped with a control cock (not shown) at a suitable distance from the vibrator. The exhaust air is conducted away from the vibrator by the outer flexible hose l5, which permits its submersion to any desired depth. The hose, also serves as a hand-line by which theoperator lowers or casts the vibrator into successive portions of the concrete mass, controls its location and po'sitiontherein, and withdraws it therefrom.

In detail the construction of the vibrator is as follows: Into the lower end of the metal cylinder I0 is screwed the solid extension piece ll into which, in turn, is screwed a wearing plug l6, made removable for easy replacement. To the upper end of the cylinder Iii the" exhaust'hood I8 is secured by means'of the pins I 9. The top of 20 which fits into the top or cylin der ID, a tight jointbeing obtained by the gasket 2L On top of the cylinder head is screwed the hose coupling 22 into which the outer" hose i5 is clamped by the expanded metal ring 24; The inner hose l4 is clamped in the topofthe cylinder head 20 by this hood is threaded to receive the cylinder head end abutting the upper face of the wearing plug Hi. The elastic casing I2 is shown in Figs. 1, 3, and 4 dilated as it would be when subjected to internal air pressure. Fig. 5 represents it as contracted. To limit the extent of its dilation under pressure it is provided with sinuous co-r'ds '29 (Fig. 5) which are molded into the rubber or other elastic material. Upon dilation of the casing the sinuous bends are straightened out and the then circular cords serve to limit the extent of the dilation, especially when the vibrator is not immersed or only' partially immersed' The casing I2 is made of'such a diameter that when assembled on the members which support it it is under appreciable tension around them. Each rapid expansion and subsequent rapid contraction of the casing produces respectively a compression and rarefaction in the surrounding material, which together constitute a complete vibration. In order to produce rarefaction pressures appreciably below atmospheric, while still employing exhaust pressures equal to or greater than atmospheric, it is necessary that the casing be under suitable circumferential-tension, even in the contracted position.

The automatic valve mechanism, which is contained inside the metal cylinder l0, comprises a reciprocating piston valve 39 through which ex- Y tends aidally an air passage 3|. The ends of the piston valve are identical, thefupper end havin a valve head 32 which slides in the cylindrical chamber 34 in the cylinder head 20. The lower end has a similar valve head 35 which slides in the cylindrical chamber 36 in. the extension piece |j|. The chambers 34 and 36 are each provided with three grooves or scorings (see Figs. 1 and 4), those in the cylinder head 29 being designated 38 and those in the extension piece designated 44. These scorings are for the passage of compressed air around the valve heads in a manner which will be described in conn ction .with the explanation of the operation of the valve.

' The piston valve 30 also carries the upper piston head 40 and the lower piston head 4|, each machined to closely fit the inside of the cylinder III: In the wall of the cylinder I0 adjacent the piston heads 40 and 4| aregrooves or scoreings 42 and 39, for the passage of fluid past the respective piston heads for purposes described in explaining the operation. Each of the piston heads 40 and is provided with an annular.

clearance pocket 45, as shown in the broken section of the piston head 4|. T,

For the admission of compressed air or other fluid to the inside of the elastic casing-l2, inlet ports 46are provided in the extension piece communicating 'with'the chamber 36. With the reciprocation of the piston valve 30 these ports are alternately covered anduncovered by the valve head 35. r f

For the escape of the fluid from theinside of casing l2 exhaust ports 48 are provided adjacent the piston head 4|. With the reciprocation. of the piston valve 30 these ports are alternately covered and uncovered by the piston head 4|. The exhaust fluid travels upwardly through cylinder l0 around the piston valve 30 and enters the exhaust hood-l8 through theexhaust openings 49,

from whence it escapes into the outer hose l5 through the holes 50 in cylinder head 20.'

In Fig. 6, a vibrator is shown in position to gizbrate a mass of concrete 5| held between forms The operation of the vibrator will now be de-. scribed, taking up first, the manner of reciprothe lower piston head 4| escapes only inder I0 and the chambers 34 and 36, in so far as they effect the reciprocation of the piston valve 30. The reciprocation is produced by compressed air admitted and exhausted through air passages of restricted capacity, namely, the inlet scorings 39 and 44 and the exhaust scorings 42 and 39, which passages are opened and closed by the valve heads 32 and '35, and piston heads 40 and 4 respectively.

Compressed air is made available to the upper end of the piston valve 39 directly from the supply hose l4,- and flows through'the axial passage 3| throughout the length of the piston valve 30, thus supplying compressed air to the lower chamber 36.

With the piston valve 30 starting upward from a position of rest at the bottom of its stroke, the action on,the piston heads 49 and 4| is as follows: The lower inlet scorings 44 are open and the lower exhaustscorings 39 are closed by piston head 4|, while the upper inlet scorings 38 are closed by valve head 32 and the upper exhaust scorings 42 are open. Thus compressed air, admitted under the lower piston head 4| starts the piston valve 39 on its upwardstroke.

on reaching mid-stroke position the lower inlet scorings 44 are closed, and the lower exhaust scorings 39 are about to be opened, while the upper exhaust scorings 42 are closed and the upper inlet scorings 38 are about to be opened.

As the valve 39 travels upward the air under gradually, due to the restricted capacity of the exhaust scorings 39. Alsoydue to the restricted capacity of the inlet scorings gradually on the upper piston head 40. As a result of these conditions and of its own momentum, the valve.30 continues on its upward stroke until it rebounds downward upon the upper piston head's striking the cylinder head 29. By this time the pressure on the upper piston head 40 has materially increased, and the pressure on the lower piston head 4| has materially decreased. The valve 33 is thus driven downward with increasing speed.

Upon the'valves reaching mid-stroke position of the downward stroke, in which position it is shown in Fig. 1, the cycle of events just described is repeated except that the role of the ends is reversed and the direction of movement'is oppo- 38 pressure is built up. only site. Upon reaching mid-stroke position of the I upward stroke the complete cycle is repeated. Thus the piston valve 39 continues to reciprocatein the desired manner.

By means of the reciprocation oi. the piston valve 30 the inlet ports 46 in the extension-piece and the exhaust ports 48 in the cylinder l9 are alternately opened and closed. During the interval in which the valve is above itsmid-stroke position the inlet ports 43 are open, and com pressed air is admitted between the outside of the metal cylinder l0 and extension-piece land therubber casing l2, thus dilating the casing, and when the valve 30 passes through mid-stroke position on its downward stroke the inlet Sorts 46 are closed and the exhaust ports 48 are opened. This permits the casing to expel. the air from between the cylinder l and extension-piece II and the casing i2, by' contracting. The exhaust ports 48 remain open until/the piston valve 30 passes'mld-stroke positiori'on its upward stroke,

.at which time they ,are'closed by the piston head II and the inlet ports 46 are opened by the valve head .35. Compressed air is thus admitted to dilate the casing l2 asabove described, the cycle air have been provided for the operation of the valve, if desired, the functions of both sets of ports may be served by one -set of ports alternately connected to the pressure supply and the exhaust conduit by the piston valve in a manner known to the art.

Also, while an apparatus has been shown in which both inlet and exhaust valves are employed for admitting and permitting exhaustion of air from within the extensible casing,if desired, either one of these valves may be omitted and a throttling passage of suitably restricted capacity employed in its stead. v

Additional vibration of the material in which the vibrator is immersed will be caused by the reciprocation of the piston valve 30, which, 'as just described, successively strikes the cylinder head 20 and the extension piece ll. As is obvious, these impacts of the'piston valve will cause a vibration of the device along its longitudinal axis. These impactive vibrations thus generated are communicated to the material through exten- 1 sion piece H and the wearing plug l6, facilitating the introduction of the vibrator into. stiff plastic or granular materials, and assuring the solidification of the material beneath the vibrator as itis withdrawn therefrom. The piston valve3ll is of course so constructed, in ways known to the art, that the impacts will not interfere with its continued functioning.

While the embodiment described has an elastic rubber casing it is within the purview of the invention to use any form of outer member which is capable of undergoing volumetric changes when subjected to varying pressures. For example, a flexible metal tube either elliptical or square in cross-section would, under increased pressure, undergo volumetric expansion. wise the outer member might consist of rigid members secured to flexible anchorages so as to move bodily under pressure fluctuations.

While I have shown and described a preferred embodiment of my invention, it is to be understood that thefinvention is not limited to the particular embodiment disclosed, but includes such modifications and variations as come within the spirit of the invention and within the scope airtight at its ends, and automatic valve mechanism for admitting fluid under pressure to the inside of said member and exhaustingit there- Like-' from to produce volumetric changes in said flexible member.

3. Vibration generating apparatus operating directly from constant fluid pressure comprising a support having a. chamber therein, a sealed elastic member secured to said support, automatic valve mechanism in said chamber adapted to intermittently admit fluid under pressure into said elastic member and to exhaust it therefrom, and means for supplying fluid under pressure to said valve mechanism.

4. Vibration generating apparatus adapted to undergo volumetric fluctuation comprising an airtight flexible member, a hollow cylinder within said member having inlet and exhaust ports for fluid under pressure communicating with the interior of said member, an automatic pneumatic valve in said cylinder adapted to alternately open and close said ports, and means for conducting,

fluid under pressure to and from said ports.

5. In apparatus for generating vibrations by volumetric fluctuations resulting from fluctuations in fluid pressure in an elastic member, automatic valve mechanism for controlling the flow of fluid comprising a reciprocating piston valve, a cylinder within which said valve slides, a piston head near each end of said valve and fitted to said cylinder, restricted exhaust passages in the wall of said cylinder adjacent to and controlled by said piston heads, a valve head on each end of said valve each fitted to slide in its own chamber, restricted inlet passages in the walls of said chambersthrough which the flow of fluid into each end of said cylinder is controlledby said valve heads, and inlet and exhaust ports communicating with said elastic member and controlled by the reciprocation of 'said piston valve.

6. An expansible casing for apparatus adapted to generate vibrations by volumetric fluctuations consisting of a cylindrical body of elastic substance having embedded sinuous members to'limit the extent of expansion of the casing.

7. In vibration generating apparatus of the volumetric expansion type, the combination of a rigid supporting member with an elastic expansible member, said elastic member being applied to said supporting member under substantial tension.

8. Vibration generating apparatus comprising a hollow cylinder, an extension piece secured to one end of said cylinder, a cylinder head secured to the other end .of said cylinder, an automatic piston valve arranged to reciprocate in said cylinder, a flexible casing arranged exteriorly of said cylinder'and extension piece and secured airr tight at its ends, means controlled by said valve for admitting fluid under pressure to said casing,

- means also controlled by said 'valve for permitting the fluid to exhaust from the casing, and

. means for causing the piston to reciprocate when fluid pressure is appliedthereto.

9. Vibration generating apparatus for plastic able from a unidirectional flow of pressure fluid to interrupt said fiow with high frequency.

11. In apparatus for treating plastic or granular materials by vibration of a member volumet 5 rically responsive to fluctuationsvof internal fluid pressure, the combination with such member of means producing other vibrationsby the acceleration of a mass, and means for communicating the last mentioned vibrations to the material to be 10 treated so as to facilitate the insertion of the apparatus into the material. V

12. Vibration generating apparatus for plastic or granular materials comprising a flexible member capable of volumetric expansions, mechanism 15 associated with said member for producing said expansions, and means for manipulating said member and said mechanism together for insertion into said materials to vibrate the same.

13. In vibration generating apparatus for plastic or granular material, the combination of an element capable of immersion. in said material,

said element comprising a volumetrically expansible member and mechanism for producing volumetric expansions of said member, and means for supplying energy to said mechanism.

14. In apparatus for generating vibrations in a mass of plastic or granular material, the combination of a unit comprising a volumetrically expansible member and mechanism for produc-, ing volumetric expansions of said member, with means for supplying energy to said mechanism, and means for manipulating 'said unit, said unit being capable of insertion into said materials to vibrate the same.

. EDWIN H. LUDEMAN, JR. 

